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350-501 · Question #393

Refer to the exhibit. The service provider is serving hosts with two different multicast streams from source X and source Y. Source X is multicast group 224.0.0.0/8, and source Y is multicast group…

The correct answer is B. Add ip pim bidir-enable in global mode on RB. The network needs to support bidirectional PIM for Source X using RP 10.20.1.1 and regular PIM Sparse Mode for Source Y using RP 10.20.2.1. Enabling ip pim bidir-enable on RB allows it to participate in or act as a Bidirectional PIM router, which is crucial for the first…

Networking

Question

Refer to the exhibit. The service provider is serving hosts with two different multicast streams from source X and source Y. Source X is multicast group 224.0.0.0/8, and source Y is multicast group 226.0.0.0/8. Multicast source X should send its stream through bidirectional RP address 10.20.1.1, and multicast source Y should send its stream through RP address 10.20.2.1. Which configuration meets these requirements?

Exhibit

350-501 question #393 exhibit

Options

  • AEnable ip pim ssm default on RA and RB.
  • BAdd ip pim bidir-enable in global mode on RB.
  • CPermit the source X and source Y IP addresses in the access list on RB.
  • DSet PIM sparse mode with a static RP address of 10.20.2.1 on RA and RC.

How the community answered

(39 responses)
  • A
    3% (1)
  • B
    92% (36)
  • C
    5% (2)

Why each option

The network needs to support bidirectional PIM for Source X using RP 10.20.1.1 and regular PIM Sparse Mode for Source Y using RP 10.20.2.1. Enabling `ip pim bidir-enable` on RB allows it to participate in or act as a Bidirectional PIM router, which is crucial for the first requirement.

AEnable ip pim ssm default on RA and RB.

Enabling `ip pim ssm default` configures Source Specific Multicast, which uses (S,G) channels and does not involve RPs or bidirectional PIM functionality.

BAdd ip pim bidir-enable in global mode on RB.Correct

Adding the `ip pim bidir-enable` command in global configuration mode on RB enables Bidirectional PIM functionality on the router, which is a prerequisite for supporting a bidirectional RP for multicast group 224.0.0.0/8 as required. This command allows the router to create and maintain shared trees for bidirectional groups, enabling many-to-many communication.

CPermit the source X and source Y IP addresses in the access list on RB.

Permitting source IP addresses in an access list is typically used for defining valid sources or for RP-group mappings, but it does not enable bidirectional PIM itself.

DSet PIM sparse mode with a static RP address of 10.20.2.1 on RA and RC.

Setting PIM sparse mode with a static RP for 10.20.2.1 on RA and RC addresses the second requirement for Source Y but does not enable bidirectional PIM for Source X.

Concept tested: PIM Bidirectional (Bi-dir) configuration

Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti/command/imc-cr-book/imc-i2.html#wp2506240228

Topics

#Multicast Routing#PIM#Bidirectional PIM#RP Configuration

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